Objective:Medical treatments take place in social contexts; however, little research has investigated how social modelling might influence treatment outcomes. This experimental pilot study investigated social modelling of treatment effectiveness and placebo treatment outcomes. Design:Fifty-nine participants took part in the study, ostensibly examining the use of beta-blockers (actually placebos) for examination anxiety. Participants were randomly assigned to observe a female confederate report positive treatment effects (reduced heart rate, relaxed, calm) or feeling no different. Main outcome measures:Heart rate, anxiety and blood pressure were assessed, as were symptoms and attributed side effects. Results:Heart rate decreased significantly more in the social modelling compared to control condition,p = .027 (d = .63), and there were trends towards effects in the same direction for both anxiety,p = .097 (d = .46), and systolic blood pressure,p = .077 (d = .51). Significant pre-post placebo differences in heart rate, anxiety and diastolic blood pressure were found in the social modelling group,ps .28 (ds = .09–.59). Conclusions:Social observation of medication effectiveness enhanced placebo effectiveness in heart rate, and showed a trend towards enhancing treatment effectiveness in both anxiety and systolic blood pressure. Social modelling may have utility in enhancing the effectiveness of many active medical treatments.